public class Main {

    /**
     * Hello World!
     * Demo.toString() = Main@1540e19d  8
     * Demo.toString() = Main@2ac1fdc4  9
     *                  $MAJOR.$MINOR.$SECURITY
     * @param args
     */
    public static void main(String[] args) {
        System.out.println("Hello World!");
        System.out.println("Demo.toString() = " + new Main().toString());
        String version = System.getProperty("java.version");
        System.out.println(version);
    }
}

class Demo{
    private String name = "Demo";
    @Override
    public String toString() {
        return name;
    }
}
